As electronic parts commonly-used in mobile phones, mobile computers and other electronic products, micro speaker modules offer people conveniences in many aspects such as communications and entertainment in life. At present, the development trend of the mobile phones and other devices is thinner, smaller in size, and better in function. Accordingly, the sizes of various parts in the mobile phones also need to be further miniaturized.
The micro speaker module is a component that occupies a relatively large space in the mobile phone, so how to reduce the size of the micro speaker module is the key to further reduce the thickness and the size of the mobile phone. The main research and development direction of the person skilled in the art is to reduce the cost of the space occupied by a micro speaker. At this stage, the main means of reducing the size of the micro speaker is performed by changing layout and structural characteristics of all components of the speaker as well as reducing the size of each component. For example, it is implemented by reducing the size of a voice coil and a magnet. Accordingly, while reducing the size of the micro speaker, the performance of the micro speaker also needs to be continuously improved, avoiding the reduction of the performance caused by the size reduction. Therefore, how to improve the performance of the micro speaker has become another main research and development direction for those skilled in the art. The improvement of the performance of the micro speaker mainly relates to the characteristics of enhanced magnetic field intensity, more free vibration of a vibration diaphragm and the voice coil, larger vibration amplitude and the like. At present, the main research and development direction of the person skilled in the art is to reduce the size of the micro speaker and to improve the performance of the micro speaker.
However, the inventor of the present invention finds in a case that the size of the micro speaker is reduced and the power is increased, more heat is generated during operation, which is a factor that restricts its own performance. When a micro speaker module relatively high in power operates, the voice coil will generate more heat, resulting in substantial temperature increase of a speaker structure. As the size of the micro speaker is too small to immediately release heat, the temperature of parts, such as the vibration diaphragm, the magnet, an injection-molded shell, around the voice coil will be substantially increased. Those skilled in the art are not aware that the combined factor of reduced size and increased power can cause a significant high temperature problem. If the internal temperature of the micro speaker module is too high, it will cause the following problems that the vibration diaphragm becomes soft, the magnet is demagnetized and the injection-molded shell is deformed, eventually leading to performance degradation, or even failure of the speaker. Therefore, the inventor of the present invention realizes when the operation power of the micro speaker is increased, heat resistance of respective components of the speaker and a heat dissipation capacity of the speaker system become an obstacle in the way of improving the overall performance of the speaker.
In general, when the speaker temperature is too high, in most cases, the heat dissipation capacity of a product can be improved by using a pure metal shell or adding a metal cooling fin. However, for a micro speaker used in a communication terminal such as a mobile phone, a shell containing too much metal will affect the performance of an antenna near the speaker and hinder normal operation of the antenna and related parts. On the other hand, the size of the cooling fin cannot be too large due to the limited size of the micro speaker module, so ideal cooling requirements cannot be met generally. While it is inevitable that the number of components inside the speaker is increased after the cooling fin is arranged, so the space required and occupied by the speaker is increased. Therefore, arranging the cooling pin in the micro speaker cannot effectively solve the heat dissipation problem, instead increasing the size. Thus, the inventor of the present invention believes that it is necessary to provide a solution which can provide an excellent heat dissipation environment without affecting the normal operation of the antenna or the other related parts, or increasing the size of the micro speaker.